Eye-testing instrument



Dec. 21 1926.

H. L. DE ZENG EYE TESTING INSTRUMENT File d Nov. 12 1921 4 Sheets-Sheet l INVENTOR ATTORNEYS Dec. 21 1926. 1,611,167

H. L. DE ZENG EYE TESTING INSTRUMENT Filed NOV. 12 1921 4 Sheets-Sheet 2 i v ATTORNEYS Dec. 21 ,1926; 1,611,167

L. DE ZENG EYE TESTI NG INSTRUMENT Filed Nov. 12 "1921 4 Sheets-Sheet 3 lllIlllIllIyIIIII/(I nun/"1, 1,11,15 r

ATTORNEYS Dec. 21, 1926.

' H. L. DE ZENG EYE TESTING INSTRUMENT Filed Nov. 12, 1921 4 Sheets-Sheet 4 Patented Dec. 21, 1926.

. .lfiliglm Parse-r m re E.

HENRY L. :on ZENG, or 'ivroonnsrown, New JERSEY, essrenon roni znne 'sreniplian Y Q O Y ,Q M EN E3$ YrA wer -s ms JE S .er -res m les evnmwi.,

i Application fi-led- November This invention'relates to new ophthalmologlc lnstrumentused inmeasuring therefraction of the eyeand in testingitsmotor musclesi v 7 v The principal object of theinventionis to provide" in highly condensed form an instrument by thexuse of which 'the'ey'einayhe measured for glasses designed to correct any existing" errors in the retracting-media of the eye orirnbalances in its motor muscles. A further object of thexi nvention is to 7 provide a binocular instrument having every facility for testing the eyesseparately and finally together, wherein the. cylindrical lenses used in the correction otastigmatism are confined to carriers of lim ted CllIIlGHSLODS for the avoidance of conflict with thenose of the person under examination'when setting the cylinder lenses to. any required axls,

Another obzgectof the invention consists I in providing cylindrical lensattachments-in hinoc.ular,form and of such design as to avoid conflict between the batteryfof the 'cylinderlenses on one side and that onzthe' otherside when settingthe. lenses at any desired axis before either eye and especiallyv whenth e instrument is adjusted to ineet'the narrower interpupilaryrequirements of cerand furnishing exact means for displacing tain patients including children Another object of theinven'tion is toipro- 'vide an instrument with as few: lenscarriers as possiblewithout undulyvlimiting the range of focalpowers of eitherthe spherical.- orwcylindrical lenses.

Another object of my ride an instrument wherein-the displacing prisms of fixed values are carried-by means independent of theImohile or rotary prism units and which 'When in position at the sight openingoccupy a predetermined POSltion' of base, thus expediting the examination the image in muscle tests." V

Another objectiof the invention'isto provide an instrument wherein the protecting shields ott'the lensesarevutilized as lens 1 ".riers alsofor' the purpose ot-condensing the lens carrying, features to the greatest possible extent thereby PI'OQlUCIHQv-BJL lnstru- 'I'nent ,as thin as can bemade while-contain-v ing the necessary refraction" and-muscle testingelements= I 7 t invention is. to 1012 0 121921, Serial No. 514,467..

- light filtersin combination with other t es."-

ing elements of thein'strumentr f For. the purpose oi: illustrating-my invent1on,- I have shown an the accompanying -.draw1ngs a typical embodiment vthereof which is at presentpreferred'by me, since ,1

this e mbodirnent will he found in practice to glve. satisfactory and rieliable results.

ous instrumentali'ties of which my invention consists can be variously arranged endor- It i is, however, to be understood thatthe'varr' gani-zed'andthat imyinvention is not limited 7 V to the, precise arrangement and; organization .of'these instrumental ities.asiherein shown and described; e s .7

2 Figure, Irepresents a front elevation "oi? an eye testing instrument, embodying my inyentifoln y Figure 'ZLrepresents'; myinstrunient. .e 5 a Figure 3- reprefsents, in' rear; elevation, a portion; or the-instrument. V

z end. eleva on of double rotary prism unit employed. v

. F'g'uretj represents a rear elevation lot the l igure 5 represents a rear elevation off-a :Maddox multiple rod uniternployed.

figur repr sents a. section on a line 6+6- f c e "-Fignr'e 7' represents} in elevation, -.and;,-in detachedpositiom 'a front shieldjoronent the cylindrical lens t esting-,-units I jv 1' Figure Sirejoresents, in elevation, one of the rear shields, showing, more particula -ly its attachment to one of the adj usta-bleQmem- .bers of: the cylinder lens; system.

. Figure 9;,represents front elevationgoi the"the first/lens carrier in, arcylinderr lensf unit. ,7 v v c;

Figure 10 represents a front elevation the second? or. rear lens i carrier ot the unit as that OfFigureQ. j y Figure 11 representsa front elevation of as front shield-o1 the sphericallens attach 5 "Figure12 representsj a frontelevationota i first-lens carrierrof the spherical lens'attaclr cal lens attachment.

able interpupilary slides 3. These slides o scribedin detail hereafter.

the second; or rear lens carrier of the spheri- Figure 14 represents a rear elevation of a shield or cover forv the spherical lens attachment.

Similar numerals of reference indicate corresponding parts.

Referring to the, drawings.

In my copending'application Serial No.

457,782, upon which Patent No, 1,483,786

issued on February 12, 1924:, for an ophthalmological instrument, I have described and broadly claimed a novel eye testing instrument which can be employed for the same purposeas my present mventlon. In

myfpresent invention, however, certain of the units which make up the instrument have a different arrangement and collocation particularly the lens carrying disks and covers thereof, whereby certain. supple- -Inentary lenses are mounted within the dust are each provided with laterally projecting arms 4, which, in turn, carry the testing units comprising the spherical lens units 5, the cylindrical lens units fi, the double rotary prism units 7 and the Maddox multiple rod units 8, all of which will be de- 7 The spherical lens units 5 are supported by a bracket 5) rising from the rear end of the rearwardly projecting supports 4. The lens units 5 include two dial plates 10 and 11,see more particularly Figures 12 and 13,'and also two auxiliary combined shield and lens carriers '12 and 13, respectively, see more particularly Figures 11 and 14. r

The parts 10, 11, 12 and 13 are pivotall -r supported at 14 on a bracket 9, Mounted in the front dial plate 10 are seven sphen ical lenses'15, and'the dial plate is provided with a sight opening These spherical lenses 15 range preferably from 0.25 to 1.7 5 diopters, inclusive,in steps of quarter di'opters in the positive denomination. Mounted in the rear dial plate 11 are seven spherical lenses 17 and this/rear dial plate also has a sight "opening which is desi nated 18. Some of these spherical lenses 17 are of minus power and some are of plus power, the plus powers being preferably 2.O0,. 1.00'and 6.00 diopters and the minus powers being preferably 2.00, 4.00, 6.00 and 8.00. diopters. The powersv of the carries auxiliary lenses referred to are marked on the front faces of the dials carrying these lenses, as indicated in Figures 10 and 11. In each instance, thenumb'er indicates preferably the lens opposite to it'on the other side of the dial. I

The front cover plate 12 has a plurality of openings 19, see Figure 11, througl'i which the focal numbers ofthe lenses carnee by the dials underneath are visible as said lenses are brought into operative position at the sight opening. The front cover plate 12 is provided with a handle 20 for rotating it;

lenses preferably follows ':-a'+0.12 diopters spherical lens 21, a six diopter displacing prism 22, a ten diopter displacing prism 23 and a fifteen diopter prism 24. a It is also provided with a sight opening'25. It also has index num- The cover plate 12 bers indicated on its face, indicative of the;

lens diametrically opposite. The rear shield and lens carrier 13 is provided with a handle 26 and with a sight opening 27, and carries a plurality of auxiliary lenses including preferably a color filter 28 which is preferably red, a. plus 8.00 diopter spherical lens 29 and .a minus 10. diopter spherical lens 30. The lens carriers or dial plates 10 and. 11' are preferably peripherally knurled in order to facilitate their rotation by the fingers of the operator.

The. number of spherical lenses and their powers may be varied in accordance with conditions and requirements met with in practice for increasing 'or decreasing the range of powers obtainable inthe instrument. lenses at the-sight opening, a multiple bearing spring clip 31 is provided for each dial, see moreparticularly Figures 2 and-6. Rotative pressure on the dial wheel will release the spring clip sothat the dial wheel may be advanced as desired. The construction and arrangement of the multiple bear ing'sprlng clips is the same as that dis closed in myPatent l lo. 1,433,786 aforesand and a detailed"description is therefore believed to be unnecessary.

Each cylindrical unitt is supported by its respective bracket 9. This unit is nradei up of front and back coverplates 32 and 33,

respectively, see more particularly Figures 7 and 8, and fronfiandback lens dials or carriers 34: and 35, respectively, see more.

particularly Figures 9 and 10, which are pivotally supported in'the cover plates at 9 The front'cover plate 32 is provided with .a sight opening 37,and the rear coverplate 1s provided with a sight opening 38, see,

more particularly Figures 7 and 8.- The frontcover plate covers one or moreopenings 39 through which the focal power indicators of the cylinder lenses arei l- To insure correct positioning of the 'Lil when the same arein operative" positional the sight opening,

Inthe dial 34, see Figure 9,ar'e-'preferably i iiour cylindrical lenses 40, and a sight opening 41 is provided; These cylindrical lenses are preferably 0.25, 0.50, 0.75'and 1.00 diopters in negative power; The powers of I these lenses are also indicated on the dial,-

see Figure 9, each index indicating the lens diametrically opposite to it. The dial 34" is provided with'openings '42 through which the indexreadings on the dial 35 are visible when, the same are in operative position at of the lensdiametdcally opposite to it.

Inthe invention here shown, all cylindrical lenses are of minus denomination but the invention; may embody similar cylindrical lens attachment with all cylindrical lenses of the plus denomination orfurthe'nmore.

any combination of" plus and minus denomination required to meet conditions of operation'may be incorporated.

,Vhile the cylindrical lenses contained in the invention as shown are of minus charac ter and are mounted in their respective cells with their axes radial with the dials or lens carriers, they may be mounted in their cells.

with their axes in any desired position, in which latter case the index and scale-read ings may all be so. arrangedthat each successive lens will come into operative position with its axis in a predetermined merid-- ian. The peripheral edges'of the cylindrical dials 34 and 35 are preferably knurled to facilitate their rotation.

The required cylindrical powers 'ar'eob tained through employment of V the lenses in the dial, singly or in'combination, by ex posing one or two lenses at the sight opei ing as required forobtaihing-the required cylindrical lens focal equivalent It will be noticed that in my present invention 1 have confined the diameters of the cylindrical lens attachment to within certain limitaf tions for the purpose or avoiding conflict with the nose of the patient and conflict btween the two said attachments when used binocularly. this construction is unique because orlits compactness and adaptability to binocular eye testing instruments. Itis alsoexceed ingly simple in its construction and mode of operation. The cylindrical unit 6 is eccentrically positioned with respect the main sight opening 37, the Whole cylinder unit being rotatable about the center of saidsight opening for the procurement of thefrequired cylinderaxes. On the bracket 9, contiguous with the rotatable disc wh1ch carries It is therefore obvious that the cylinder ui'iit'6, is a' degree scalef lfiwhich" required cylinder lens axis. 'The cylinder units need only a rotation ottl80" Obi-2111'! the various axes required in eyetes'ting.

The cylinder jleiis units"arei'adjustab'ly mounted on'the bracketl for the-ad ustment required in) obtaining the gvarious cyhn'dr1- cal axes in the following "manner,see more particularly' Figure 6. V I 7 49 design-ates a disc nrotatable in the bracket '9=," the",disc' and bracket ibeing-recessed to receive' a friction ring througli which passes: fasteningfdevices 51 which also passthrough the 'disc49 and are connected with the disc 45; ,iThi'sdisc 45 has a central: sight opening 52 whichz'also extends through The friction ring is prefer:

the disc? 49. u I ably concaved so thatithetensionmay be adjusted in accordance withthemequire ments in. holding theeyliiider' units in any This ring is made'pr'ef desired position. H erably of spring metal, and, inth'e position shown in the drawing, is flatff 53 designates eye cups carried by fixtures 54 which are mounted at 14and 55 on the brackets 9. While in'the present invention I haveshownthe eye cups" 53 as being a-t-.

' actsin co op eratioh with "the" indicator 47' to" indicate the axis of the cylinder when int 7 operative position at the sight'open'ing -'37 The whole-cylinder unit may be turned by the handle 48 for the procurement oi' the" an i tache-d t0 the'inst rument, neverthelessithey may be detachably mounted for sterilization purposes when so desired. Furthermore V these'eye 'cups maybe adapted to re'ceiv'e covering 'material' for sanitary purposes.

The rotary prism units 7 are providedvwith a bracket 56 mounted at 4, see Eigiire:"1. Rotatably mounted in theubracke-ts 56 are double rotary prisms 57 whereby any desiredp-r'ism equivalent, iangnigirom zero to fir;-

teen prism diopte'rs, may j be obtained by turning the. pinion =58,- aseindic'ated, upon the dioptrix prismscale 59 on the face of'thc prism case" and theindicator v60 placed upon the prism cell-61'. v Surroundingthe prism case is a degree. scale'bQ,which, acting an co-operationwitha-line' indicator on oppo-v sitessides of the prism case at the l5;di.opter reading of the-prism scale'provides exact means for "lOCfitlllgil'lB base vof the derived prism equivalent in' any. desired angular position before the "eye. The mobile prism unit is of customary construction and containstwo prisms of equalval ue, each ear- V l'ied in a separate cell," each having gear teeth about its outer periplierywhich' engage a pinion locatedbetween the-nu Theaction of the-pinion gives theprisins inverse rota tion'and consequent resultant prism equiv'alents, as indicatediby the scale;

As my invention here shown is abinocular I, 7

testing instrumenui the testing funits on either side are frequentlywrequired for use" at the same time, and, in consequence, these units including the Maddox multiple rods and the double rotary prisms must be of such proportions as will admit of their po-' sitioning in line with the sight openino's without interference, or, in other 7 words, without the inner edges of the mountings of said units conflicting when. th is adjustedto meet the requirements of pa tients having small interpupilary measure ments and-particularly those patients and children having an interpupilary measure ment of fifty-four mm. or less. In prior constructions of eye testing equipment of binocular character, these Maddox rods and rotary prism units have been considerably larger in diameter and in consequence is; id units could not be employed collectively 1 the testing of the eyes of patients havi interpupilary measurements of comparativ ly narrow degree, and could not reachinterpupilary measurements of fifty millimeters or less without the inner edges of themounting striking and thereby preventing a prop,- er alignment of the units with the line of observation. '7 r The MaddoX rod units 8 are provided with brackets 63 which are pivotally mounted at l Rotatable plates 64 are rotatably mount ed in the brackets'63 and are provided with an actuatlng handle 65. The Maddox rod lens 66 is of white glass and is mounted in 7 its rotatable plate 64. Partly surrounding the plate 64 is a degree scale 6. carried bythe bracket 63, and whlch, 1n co-operation with indicators 68, provides means for determining an oblique positioning of the optical axes of Maddox rod lenses.

69 designates a level in fixed relationship with the slide supporting mechanism and adjusted by means of the screw 70. 71. designates an interpupilary scale which cooperates with a pointer 72'.

The slides 3 are relatively means of the screw 73. 'l ldesignates stationary discs having openings 75 through which the focal index numbers of only those lenses which are in operative position can appear. To make an examination with this eye testing instrument, the distance between the sight opening is adjusted to conform with the interpupilary dimensions of the patient by means of the screw 73' In testing one eye the other is blanked by the rotation of the rear shield 13 (see Fig. 141) to cover the sight opening. The refraction of the eye is then tested through the use of the spherical and cylindrical lenses which are moved into place through the rotation of their respective'dials; VVhen the refraction of the first eye-is tested one shield is rotated to uncover the sight opening and the other shield is rotated to, cover the sight opening so that the other eye can be tested in a similar manner. NVhen both eyes have examination.

instrument adjusted by been tested the'shields are rotated to'leavc both eyes unobstructed and in thefield of With a small. point of light as a test obect located -five or 81X meters distant from the instrument, a Maddox multiple rod unit 8 is placed in alignment on the side corresponding to the eye under test rugations or axis vertical. The eyeunder test will then see a horizontal streak of li rht while the other eyewill seethe original point of light. Should the streak cut lite point of light a proper vertical co'-ordination of the visual lines of the two eyes wor rf be indicated. With the Maddox rod set with axis horizontal, the streak of light-'would then appear in a vertical plane and should this streak cut the point proper horizontal coordination of th visual axes of the two eyes would be indicated; Sho ld the al; fail to cut the'point when in he posi*.on, a laclr proper coordination would be indicated, and atest of the motor muscles of the eyes should then be made in the following with its cor-- manner: To test the lateral balance of the muscles of the right eye the displacing prism 22 with base up carried by the front shield if the lower object appears at the left'an outward turning of the right eye would be indicated and'in either instance a measurement of-the degree of imbalancethus sho n could be made by placing the double y prism unit 7 in operative position and then turning on prism power based out or; in re-.

spectively' in such degree as to cause thelower object to come into vertical al with the upper object,,the imbalance being known as esophoria when the correcting prisn base is out, or exophoria when the prism base is in.

When testing for muscles similar procedure is followed, ex-

cepting that in that instance the displacing prism 23" is employed with the prism base in and the double rotary prism unit n this instance would be located with zero imbalances of the vertical graduationhorizontal and the prism power employed base up or down as may be neces v sary to cause the true image seen. by the left eye and the false image seen the right eye to come into horizontal alignment. This test islniown as the monocular muscle test.

, Referring again tethered color screens 28 carried by the rear shields13 of the spherical lens attachments 5, these color. screens may be advantageously employed m other colors not heretofore used in instruv ments of this character, notable among them being substances adapted to selectively retard certain port-ions of the visual spectrum. :These substancesmay likewise be employed in the Maddox rod lenses 66, in the prisms constituting the double rotary pr1s1n7, or in the substance of any or aid of the lenses contained in theinvention or otherwise incorporated intothe construction in any desirable and practical manner, such light-filters being of undoubtedvalue inobtainiiig cer tam reactionsofthevision and fusion centersf e uently important in making com 'plete and scientific eye exammatlons. v

It will now be apparent that I have d vised'a novel and useful construction of an eye testing instrument which embodies the 'fea-turesof advantage enumerated as desir- "able in the statement of the invention and the above description, and While have in the "present instance, shown and described a preferred embodiment thereof which will of rotary prisms on the bracket positioned.

give in practice satisfactory and reliable results, it is to be understood that this embodiment is susceptible of modification in various particulars without departing from ficing an'y of its advantages. 7 v

-Having thus described my invention, what I claim as new and'desire to secure by Letterslc atent,is:- V i r ll'In anfeye testing instrument, means for inereasing the accuracy of prism readthe spirit or scope of the invention or sacriings comprising a" support having a sight openings rotatable'support having a prism lens'fiXe-dly mounted therein'with the thick} est partfof the prism in ,a'predetermined position and out of line with the sight opening, means to align the prism with the sight opening by rotation of the rotatable member, a second support, a bracket pivotally mounted on the second support,a pair out of line with the sight opening but adapted to align with the-sight openingby -movement of the bracket onits pivot, and

means torotate the rotary prisms to obtain the desired prism power. 4 2 1 11 an eye 'testing instrument, means" "j for increasing the accuracy ofprism readlugs; comprising a support having a sight opening, a rotatablesupport havingga prism fixedly mounted therein outof line'with 'the sight opening, means toalign the prism with V the sight-opening rotation of ,the rot atable support, a second support, a bracket pivot "ally mountedon t e second support, a pair "of rotary :PIISHIS'OII the bracket. positioned out or line of the sight openingibnt adapted 7 to alig'nr with the sightopening t mwe ment of the bracketvon its pivot, and means I to turn the rotary prisms to obtain the desired prismpower.

3. In an eye testing instrument, means" for increasingithe accuracy of prism readings comprising a support having a sight opening, a rotatable support having a prism fixedly mounted therein out of line with the sight opening,mea-ns to align the'prism with the sight opening by rotation of the rotatable member, a second support, avbracket pivotally mounted on the secondsupport, apair of rotary prisms on the bracketpositioned out or line with the sight opening but adapted to align with the sight fopening by 'movement of'the bracket on its pivot, means to turn the rotary prisms, and means to indicate the prismpower.

.4. In an eyetesting instrument, means-to increase the accuracyof prism readings comprising a member havinga sight opening,

means to' support a prism fixedly in its mountings and iout of line with thelsight opening, means to move the fixedly mounted prism into line with the sight opening, means to supports'pairofrotary prisms out of V linevvith the sight opening, means to move thefpair or rotary prisms into line withthe sight opening, and means to rotatethe rotaryp risms to obtain the required prism power.

5. In an eye testingvinstrument, means to'inc-rease the accuracy of prism readings comprising a 'member'having a sight opening, means to support a prism out ofline QWltll the sight opening and fixedly in its mounting, means to move the-fiXe-dl mount ed PIISIIl lI IiJQ line with the slght opening", means to support a pair of rotary prisms out bit-line With'th-e sight opening,me ans to move the pair of rotary prisms into line vvith the sight open ng, means to. rotate the rotary prisms, and .means" 'to indicate, the prism 7 power equivalent of the movement of the rotaryprisms.

6. In an eyetesting instrument, means for increasing the accuracy of prism readi-ngs comprising a member having a s' opening, a support having a prism fine mounted therein out of line with the si ht opening and with the thickest part of the prism in a predetermined fixed position, means to'move the fixedly mounted prism ,into line n'iththe sight opening, means to comprising a member having a open ing,'means for supporting a prism noni'otatable as-respects its mounting and outiot line With the sight opening, means for movl g the prism into 'line with the sight, opening,

' V and out of line with the sight opening,rotat'-- able means for movingthe fixedly mounted I means for 'suppeaing a paire'irdmr prisms:

out of line with the sight opening, neansior moving the pair of rotary prisms iiitof"line with the sight opening and -th'e fixedly movement of the rotary prisms toas'certain" 'the'imbalance oftheeye looklng' through the sight opening;

8. In 1 an eye testing in strumentgineanfs for testing the muscular imbalance of the eye comprising a meinbe'r having sight opening, means for supporting a prism nonrotatably mounted as respects its mounting prism into line with the sightopening, means forv supporting a pair of rotary prisms out of line of the sight}'opening,l pivotal means for. moving the pair of rotary prisms into line with thesight opening,-

means for rotating 'therotary prisms to compensate the displacement of the fixedlymounted prism, and means to measure the prism power equivalent of the movement of the rotary prisms toascertain the'imbalance of the eye looking throughthe sight opening. 9. In an eye testing instrument," means for testing the muscular'imbalance of the eye comprising a member having a sight opening, meansfor supporting a prism non rotatable in its mounting and out of line of thesight opening, rotatable means for moving the fixedly mounted prism into line with the sight opening, means for supporting a P of tary prisms out of line with the sight opening, pivotal means for moving the pair of rotary prisms into line with the sight opening, and means for rotating the rotary prisms to compensate the displacement of the fixedly mounted prism 10. In aneye testing instrument, inean's for'testing the imbalance of the eye comprisinga member having a sightopening, a5

a red colored lens out of line w th the sight 7 support having a prism fixedly mounted therein with the widest part of the prism in a definitely fixed position, and out of line of the sight opening, means for moving'the fixedly mounted prismintoline with the sight opening, means for supporting a pair of rotary prisms out of linjefof the'sight, .opening, means for ,movingfthe pair of I rotary prisms into-line, with the sight opening, and means for rotating the rotary I prisms to compensate the displacement of the fixed'prism. I

11. In an eye testing instrument, means for testing the imbalance of the eye comprising a member having a sight opening,

a rotatable support having two prisms fixed- 1y mounted therein, one with the widest part of the prism. upwardly arranged andthe other with the widest partof prism outo1 line offthei sight ope Sing wardly arranged alignment the:

sight openifigbut 156th being oi-many eat sight opening, and means for-rotatingthe rotary prisms 5woom 'iensate the displace mento'fthe fixedly mounted rism aligned 'with'the sight opening.

1 2 In eye/testing usmmennmean ,for testing the imbalance" of the eye coinprising a meinberi having a sight opening,

a rotatable support having two prisms fixedlymountedtherein, vone with the widest part of the prism upwardly arranged andone na',zma1 s for m'Ovthej fixedly mounted prisms selectively into line with the fsight openiiig means for? supporting a pair of rotary' pssms outof line'fof the sight opening, master s eving the pair or rotaryprisms into line with the with the widest part of the prism outwardly arranged when alignediwith the sightopening' butboth prismsjbeing normally out of line with the sight opening and said prisms being of differentpower, meansfor moving the rotatable support to bring the" desired fixedly mounted prism into line with the sight opening, means forsupporting a pair of rotary prismsout of line'with the sight opening, means for moving the pair of-rotary prismsinto-linewith the sight open ing, and means .for rotating the rotary prisms to compensate the displacement of the fixedly mounted prism aligned with the sight opening.

13. In an eye testing instrument, means for testing with color comp-rising a member lh'avinga sight opening, means for support ing a colored lens out of line with the sight opening, means to align the colored lens with the sight opening, means for supporting a white glass Maddox rod'lens out of line with the sightopening, and means to move the white glass Maddox rodlens into line with V the sight opening,

314. In an eye testing instrument, means for-testing with 'color comprising a member having a sight opening, means to, support" having a sight opening, means for support-- ing a colored lens out of line with the sight opening, rotatable means to align the colored lens with the sight-opening, means for supporting a white glass Maddox'lens out w of line withthe sight opening,*and pivotal meansftoalign the White glass Maddox rod lens with thesight opening.

16, In 'an instrument for testing eyes,

means for testing with color comprising amember having a sight opening, means for supporting a red colored lens out of 11116,

V the sight opening. 1U

17 In an eye testing instrument, means for testing with color comprising a member having a sight opening, a support, a rotatable wheel on the support, a colored lens on the rotatable wheel mounted to be" aligned thereby with-the sightopening, a second having a sight openin on the bracket on which it may be pivotally swung into llnewith the sight opening.

18. In an eye testing instrument, 'means for testing with color comprising a member a support, a rotatable Wheel on the support, a red colored lens on the rotatable wheel mounted to be aligned thereby with the sight opening, a second sup- 3 swun into line with the'si ht o )enln b t:

HENRY- L. DE ENGQ 

